In lamellar separators, a main flow is taken in a path between lamellae, whereon suspended particles gravitationally separated from the main flow, as well as miscible liquids, are collected in the boundary layer adjacent the lamellar surfaces, from where they can slide away gravitationally from the lamellae without being essentially disturbed by the main flow. If the lamellae have substantial length in their inclined direction, there is a risk that the separated material in the boundary layer assumes such thickness that the main flow is disturbed, or that the latter once again entrains material from the boundary layer.
One ambition will therefore be to arrange the lamellae with small extension in the direction of inclination, simultaneously as the inclination is sufficiently large so that material transport in the boundary layer in the direction of inclination will be relatively rapid, while the vertical distance between adjacent lamellae will be as small as possible to minimize the length of the flow passages.
This would however result in that the lamellar stack obtained a very small width and large height, alternatively that the required lamellar pack must be formed from a plurality of such stacks, whereby baffle elements would need to be inserted between the stacks to prevent undesired flow patterns. Examples of such modus operandi are illustrated in the Swedish published application No. 7101307-2.
It will be understood, however, that in such apparatus it is not possible to afford vertical channels, which are difficult to disturb, for both light and heavy material which has left the lamellae, or alternatively that it would not be possible to prevent through flow between adjacent lamellar packs.
It is furthermore a known situation that lamellar packs for lamellar separators tend to get a very complicated structure, if subdivision of the flow paths into a plurality of parallel paths with small area is striven after.